垂向冲击膝部的试验研究

目的 通过生物力学试验,验证穿盖弹射过程中人体膝部受到舱盖玻璃及其碎片撞击时的损伤程度,为穿盖弹射救生装置的设计、研制、鉴定验收提供生理学依据. 方法 在落锤式冲击台上模拟穿盖弹射时舱盖对膝部的冲击力.根据之前试验设计的预值,打击7具下肢标本的膝部.用弹射力载荷测量系统记录打击力的值及作用时间,并计算冲力和冲量.用X线影像判断损伤程度. 结果 7次打击的峰值力为5.214～9.526 kN,最长作用时间为33.0 ms,最大冲量为91.8 N·s,最大平均冲力为4.478 kN.X线影像学诊断显示标本均未发生骨折. 结论 本次落锤冲击试验中,坐姿人体膝部（股骨远端）可承受小于9.5 kN且作用时间不超过20 ms,或小于91N·s的垂直于股骨的冲击载荷.本试验结果对确定穿盖弹射时的冲击力限值具有参考价值.

Test research on the impact vertical to knee

Objective To verify the injury degree of knee and thigh impacted by cabin glass and its fragments in through the canopy ejection by hiomechanics test and to put forward the physiological evidences for the design,development and evaluation of the through-the-canopy ejection lifesaving device.Methods The impact force produced by cabin glass or its fragment was simulated by falling hammer in impact tests.The knee and thigh of 7 specimens were impacted based on the predicted value that estimated before experiment,the impact power value and the acting time were recorded by sensor testing system and the impulsive force and impulse were calculated.The injury degree was judged upon X ray examination.Results The powers of 7 impacts ranged from 5.214 kN to 9.526 kN,the longest acting time was 33.0 ms,the maximum impulse was 91.8 N · s and the maximum average impact force was 4.478 kN.No fraction was found by X ray image diagnosis.Conclusions In falling hammer impact tests the impact load underwent by the knee and thigh （the end of femur） in sitting posture is less than 9.5 kN and the acting time does not exceed 20 ms,or the vertical impact to femur is less than 91 N· s.Those would be valuable for determining the impact threshold in the evaluation of ejection performance.